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Measurement of Microscopic Viscosity of Fluorescent Molecular Probe Doped in Biological Cell

生物细胞中荧光分子探针掺杂的显微粘度测量

基本信息

批准号：
11650037
负责人：
NAKATSUKA Hiroki
金额：
$ 0.64万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Malachite green dye molecules (MG), a kind of triphenyl methane dye, are known for their very rapid nonradiative relaxation from the optically excited state S_1 to the ground state S_0. In MG the central carbon is joined by three phenyl rings and the excited state dynamics is strongly influenced by the microscopic viscosity of the local environment. The viscosity-dependent nonradiative process is thought to be due to diffusive rotational motion of the phenyl rings of MG around their axes, which causes the internal conversion from the excited states to the ground state. The fluorescence decay time is essentially determined by the microscopic viscosity of the local environment.The application of the fluorescent microprobe to biological objects is quite interesting, because the fluorescence measurement is very sensitive and noninvasive. We measured the fluorescence decay time of MG doped in onion cells by identifying one cell to another or even the position in a cell by using an optical microscope. It was found out that the decay time varies depending on the position in a cell, or one cell to another. Although the origin of the difference of the fluorescence decay time is not known at present, the microscopic viscosity of each site is different and it may reflect the difference of the biological activity of each cell. In recent years photon counting is possible to measure the very weak fluorescence. If this method can be combined with optical fibers, it may serve as a medical diagnostic method in the future.

孔雀绿染料分子(MG)是一种三苯基甲烷染料，以其从光激发态S_1到基态S_0的快速无辐射弛豫而闻名。在MG中，中心碳由三个苯环连接，激发态动力学强烈地受到局部环境微观粘度的影响。粘性相关的无辐射过程被认为是由于MG的苯环围绕其轴线的扩散旋转运动，从而导致激发态到基态的内部转换。荧光衰减时间本质上是由局部环境的微观粘度决定的，荧光微探针在生物物体上的应用非常有趣，因为荧光测量是非常敏感和非侵入性的。利用光学显微镜对洋葱细胞的荧光衰减时间进行了测量，通过区分不同的细胞甚至细胞中的位置来测量掺入的MG的荧光衰减时间。人们发现，衰变时间取决于细胞中的位置，或者一个细胞对另一个细胞的位置。虽然目前尚不清楚荧光衰减时间差异的来源，但每个部位的微观粘度不同，可能反映了每个细胞生物活性的差异。近年来，光子计数法有可能测量到很弱的荧光。如果这种方法可以与光纤相结合，它可能会在未来作为一种医学诊断方法。